Portable sanders



Filed July 15, 1959 3 Sheets-Sheet 1 I s I I I 3 20 g M IIIHHH" H 5E H NMilt! y X2 I m m. A,

' INVENTOR.

Y J. EDWIN GUINN %//Wz%},4;

ATTORNEY Aug. 21, 1962 J. E. GUlNN 3,049,841

PORTABLE SANDERS Filed July 13, 1959 s Sheets-Sheet 2 INVENTOR. J. EDWINGUINN BY Z; (an FIG. 4 J/MW ATTORNEY Aug. 1962 J. E. GUINN 3,049,841

PORTABLE SANDERS Filed July 13, 1959 I5 Sheets-Sheet 3 J. EDWIN GUINNFIG.8 ;wz M

ATTORNEY 3,049,841 PQRTABLE SANDERS J. Edwin Guinn, Riviera Beach, Fla,assignor of onefourth to Amos E. Jackson, Palm Beach, Fla, andone-fourth to H. E. Knight, Riviera Beach, Fla.

Filed July 13, 1959, Ser. No. 826,793 4 Claims. (til. 5117tl) Thisinvent-ion relates to sanders, and more particularly is directed towardshand sanders of the belt type having the motor inside the frame and loopof the belt.

An object of this invention is to provide a power driven abrasive beltdevice suitable for arcuate and flat surface sanding.

Another object of this invention is to provide a device of the classdescribed with a driven pulley encasing the motor and connectedtherewith through a new arrangement meshing reduction gems.

Another of this invention is to provide a device of the class describedwith new and improved frame supporting all operable parts and having aminimum of weight.

Another object of this invention is to provide a device of the classdescribed with take-up roller mechanism to maintain tracking tension onthe abrasive belt.

Another object of this invention is to provide a handle for a device ofthe class described which will eliminate or minimize the effect torqueof the motor.

Another object of this invention is to provide a portable power drivenabrasive belt device suitable for abrading or cutting concave and convexcurved surfaces in nonferrous metal and some ferrous metal, wood,plastic and the like.

Another object of this invention is to provide a portable power drivenabrasive belt device suitable for smoothing and finishing concave andconvex curved surfaces of any material affected by abrasives.

Another object of this invention is to provide a port able power drivenabrasive belt device suitable for cutting or finishing concave multiplecurve surfaces.

Another object of this invention is to provide a portable power drivenabrasive belt device containing all the features described hereinincluding any power source.

A further object of this invention is to provide a device of the classdescribed which will be simple and eco nomical in construction, andlight in weight, efficient and durable in use.

This invention is an improvement in my Patent Number 2,560,102, issuedJuly 10, 1951.

The foregoing and other objects and advantages of this invention will bemore apparent from the following specification, in conjunction with thedrawing forming a part thereof, wherein:

FIG. 1 is a side elevation view of the sander, with broken lines showinga curved surface work and the position of the belt when operating onsuch work;

FIG. 2 is a sectional view taken in line 22- of FIG. 1, parts shown inelevation for clarity;

FIG. 3 is a sectional view taken on line 33 of FIG. 2;

FIG. 4 is a sectional view taken on line 44 of FIG. 3.

FIG. 5 is an end elevation of the device of this invention showing oneof a pair of adjustable handles positioned on the axis of the motors andthe center of gravity of said device;

FIG. 6 is a plan view of the device of FIG. 5;

FIG. 7 is a sectional view taken on line 77 of FIG. 5, parts shown inelevation for clarity; and,

FIG. 8 is a sectional view taken on line 8-3 of FIG. 5, with handlereleased position shown in dotted outline.

Referring to the drawings, wherein like members are c' lg given the samereference numeral, a pair of substantially Y-shaped members 1 and Itcomprise a basic frame having a driven belt pulley 2 pivotally mountedfor free rotation intermediate the planes of said frame members 1 and1', which are spaced apart by drum housing 3 incasing a motor whichtunis a shaft mounted gear 4 meshing with an idler reduction gear 4 torotate the pulley 2 through internal gears 5 meshing with the idler gear4'.

Idler aligning pulley 6 and 6' are pivotally mounted parallel to thedriven pulley 2 by pivot pin 7 and 7', respectively positioned in oneleg of the Y-shaped frame member 1 and '1', with one of the pulleys 6'being positioned at the terminal or free end of said leg, a gate leg 10is pivotally connected to the free end of the other leg of the Y-shapedframe member 1 and 1'.

The gate leg 10 is capable of yielding inwardly against the action of aspring 8 when the sander is pressed against an arcuate surface, as shownin FIG. 1; and, the outer limit of the gate leg 10 position can bereadily adjusted by the nut 11 or the bolt 12 which is pivoted to theframe members '1 and 1. Suitable lock nut or stop nut 13 is provided inconjunction with the nut 11.

A pivot pin 15 journals an idler pulley 16 between frame members 1 and 1and also ends of the gate legs it? with spacer bearings 17 positioned ineach end of the pulley 16. The iree end of the gate legs 10 havejournaled therebetween a similar pulley 16 with spacer bearings 17 inthe ends thereof receiving a pivot pin -15. The pulley 16' is adjustablewith respect to longitudinal axis of the gate leg 10, by means of arotatable member 13 receiving pivot pin 15 eccentrically, and areleasable lock nut 19.

The idler pulley 6 and 6' are positioned to have a common tangentialplane with driven pulley 2; and, the tension of spring 8 is adjusted toposition idler pulleys l6 and 16' in a common tangential plane withdriven pulley 2 when no force is exerted on the sander belt Ztl.

A flat press-plate is secured to the fixed legs of the frame members and1' intermediate the pulleys 6 and 6' and beneath the plane of the belt20 for flat surface sanding.

For heavy sanders, and preferably for smaller sanders also, the framehas a normally horizontal opposed legs 23, 23' to which the gate legsare pivoted, and a pair of vertical legs 24, 24 having a plurality ofradially spaced recesses therein to receive projections 26 on a handle27 secured to said legs 24, 24 by threads 28 on a thumb bolt 29 receivedby a tapped aperture 30 in said legs.

The handles 27 are machine-gun grip type with the projections 26diametrically opposed to be received by diametrically opposed recesses25. The recesses 25 on one of the leg 24 are aligned with the recesseson the opposed leg 24, so that with the projections 26 in a pair ofaligned recesses 25 in the leg 24 and 24' the bandles 27 are aligned andparallel.

This handles 27 are releasably secured to the legs 24, 24', by the thumbbolt 29, in the axis of the motor, which is the axis of the center ofgravity of the device.

By releasing the thumb bolts 29, the handles 27 can be rotated to anydesired common position and be in alignment for Work in any position.

For lightweight sander, a single handle may be used in which an L-shapedhandle 21 has the end of one leg thereof secured to the frame member 1along the longitudinal axis of the motor and driven pulley 2, with theleg thereof extending transversely across belt 20 and spaced from thepivot point of the gate leg 10. A protector plate 14 is positionedintermediate the belt 20 and free leg of the handle 21 by fastening tothe frame member 1.

To assure aligned tracking, the pulleys have a center crown ofapproximately three degrees.

In operation the device is quite simple and light in weight. With themotor actuated, the shaft gear 4 rotates the reduction idler gear 4',which rotates the driven pulley 2 by meshing with the internal gears 5.The sanding belt 20 is unrestrictedly rotated by the driven pulley 5 endand the idler pulleys 6, 6, 16 and 16'. By pressing the device on flatwork with the presser plate 22, flat sanding is accomplished; and, forarcuate sanding the device is pressed against the arcuate surfacepositioned intermediate the free end 6 of the gate leg and free end ofthe leg of frame member 1, the spring 8 yielding to permit the gate leg10 the pivot inwardly to provide wrap around surface of the sanding belt20 for the arcuate surface of the work.

For concave cutting or sanding the device is held in a vertical positionand pressed into the work piece or against the concave or multiple curvesurface positioned intermediate the free end 6 of gate leg 10 and freeend of the leg of frame member 1, the spring 8 yielding to permit thegate leg 10 to pivot inward to provide for belt 20 to flex in thedirection of the concave or multiple concave curves or surfaces of thework.

The sander belt 20 frequently wear or stretch in use. When such occurs,the thumb nut 19 is turned to free the eccentric member 18, which isrotated to extend the roller 16' outwardly to tighten the belt 20, andthe nut 19 is then retightened to lock the eccentric member in position.

The L-shaped handle 21 having the manual force transversely exertedcounter-clockwise and transmitted to the longitudinal axis of the motorcounteracts the inherent motor torque to assure smooth and accuratecontrol of the sanding operations with small embodiments of this device.

While the invention has been described ina certain specific form by wayof illustration, the invention is not so limited, as modifications andchanges can readily be made therein without departing from the spiritand scope thereof as defined in the appended claims.

What is claimed as new and desired to secure by grant of Letters Patentis:

1. In a portable hand sander, the combination of a pair of spacedsubstantially Y-shaped frame members, power means mounted between saidframe members, a driven pulley pivotally mounted between Said framemembers and surrounding said power means, gear reduction meansconnecting said power means and said driven pulley, gate legs pivotallymounted to the free end of opposed legs of said Y-shaped frame members,adjustable resilient means connecting said gate legs and frame members,a plurality of idler pulleys journaled in said frame members and gatelegs parallel to said driven pulley and having common tangential planeswith said driven pulley, a continuous sanding belt positioned aroundsaid pulleys, a presser plate fastened to said frame members andpositioned intermediate said frame members and said sanding belt,adjustable means for displacing the longitudinal axis of at least one ofsaid idler pulleys, and handles secured to said frame members along thelongitudinal axis of said power means.

2. In a portable hand sander, the combination of spaced frame members, adriven pulley pivotally mounted between said frame members, meanspositioned interior of said driven pulley and supported by said spacedframe members for driving said pulley, legs pivotally mounted to saidframe members, adjustable resilient means limiting the position of saidpivotal legs in one direction and permitting said legs to pivot in theother direction against the action of said resilient means, a pluralityof idler pulleys journaled in said frame members and pivotable legsparallel to said driven pulley, a sanding belt loop slidably positionedaround said pulleys, means for adjusting the axis of rotation of atleast one of said pulleys, a presser plate fastened to said framemembers and positioned intermediate said frame members and said sandingbelt loop, and an L-shaped handle having one leg thereon secured to oneof said frame members along the longitudinal axis of 7 said drivenpulley and the other leg of said handle positioned transversely of saidsanding belt and spaced from said pivotal leg to exert pressure in adirection opposite the movement of the sanding belt when in use.

3. In a portable hand sander, the combination of a pair of spacedsubstantially Y-shaped frame members, a driven pulley pivotally mountedbetween said frame members and surrounding said power means, meansconnecting said power means and said driven pulley, gate legs pivotallymounted to the free ends of opposed legs of said Y-shaped frame members,an adjustable spring connecting said gate legs and frame members, aplurality of idler pulleys journaled in said frame members, a pluralityof idler pulleys journaled in said gate legs, said driven pulley andidler pulleys being parallel and having common tangential planes, acontinuous sanding belt positioned around said pulleys, a presser platefastened to said frame members and positioned intermediate said framemembers and said sanding belt, adjustable eccentric means for displacingthe longitudinal axis of at least one of said idler pulleys, andadjustable handles secured to said frame members along the longitudinalaxis of the center of gravity of said device in a transverse positionwith respect to said sanding belt.

4. In combination with a portable hand sander, having a pair of spacedsubstantially Y-shaped frame members, power means mounted between saidframe members, a driven pulley pivotally mounted between said framemembers and surrounding said power means, gate legs pivotally mounted tothe free ends of opposed legs of said Y-shaped frame members, anadjustable bolt connecting said gate legs and frame member, acompression spring surrounding said bolt, a plurality of idler pulleysjournaled in said frame members and gate legs parallel to said drivenpulley and having common tangential planes with said driven pulley, acontinuous sanding belt positioned around a presser plate fastened tosaid frame members and positioned intermediate said frame members andsaid sanding belt, and adjustable means for displacing the longitudinalaxis of at least one of said idler pulleys, an anti-torque controlcomprising handles secured to said frame members along the longitudinalaxis of said power means.

References Cited in the file of this patent UNITED STATES PATENTS600,383 Sherwood Mar. 8, 1898 1,290,395 Steele Jan. 7, 1919 1,723,821Swan Aug. 6, 1929 1,834,059 Hopkins Dec. 1, 1931 1,916,543 Welch July 4,1933 2,060,266 Thompson Nov. 10, 1936 2,279,783 Fowler Apr. 14, 194-22,556,041 Pick June 5, 1951 2,560,102 Guinn July 10, 1951

